Strange colour

[Terry_b]

Hello,
I'm a complete newby to home brewing, but had a glut of white grapes on a Vine this year so thought I'd give it a go. The picture above is the result. These two both came from the same bucket, done at the same time, and using all the same equipment and additives. They were also both originally in plastic Demi John's, but I've siphoned off since brewing. I'm about to bottle. Both are at about 1.000 on a hydrometer.

As you can see the one on the right looks like wine. The other doesn't. And has a stronger smell.

Could anyone suggest why this is, as I'd like to avoid doing it again? And if there is anything to do to fix it that might be nice to know.

Thanks for any help and advice

 

[VinesnBines]

My guess is the one on the left is oxidized. Were they in the same Demi John or separate? Keeping the Demi John topped up and dosed with potassium meta sulfates will prevent oxidation. The wine needs a little headspace as possible in the Demi John. No more than 1 inch from the airlock or bung.

 

[VinesnBines]

Dosed with Kmeta.

 

[salcoco]

I am wondering if the containers are doing the color change. try a sample of each in the same type container, like a glass

 

[sour_grapes]

They were also both originally in plastic Demi John's

Were they in the same kind of demijohns? The left one looks oxidized; some types of plastic are permeable to oxygen, while others are not.

 

[winemaker81]

I agree, the one on the left looks oxidized. Think of rust. Oxidized wine is like rusted iron. Not good.

It's also not fixable. DO NOT mix the wines, you'll ruin the good one.

I'm not intending to be rough or insulting, but may come across that way. Some folks will think, "What if I mix?" It's a bad idea -- mixing good and bad never improves the bad. The result is always bad.

If the oxidized wine is acceptable to drink, drink it now. It will only decline. If it's not drinkable, dump it. Or give it to a friend with lower standards. [Don't laugh -- I've done that!]

Let's focus on the good wine!

It's in glass, which is good. However, it has too much head space, which means air space. Air -- which contains oxygen -- is your enemy. If you don't have more good wine, find smaller containers to put the wine in, so you don't have as much air space. To give you an idea of good space -- look at the thick part of the neck. You want the wine to come up to there. With smaller containers, think of about about having the same space.

 

[user 36973]

I'm assuming the wines have been in those containers for at least a little while. So not only does the oxidized wine have a lot more oxygen-containing headspace but it is in a thin plastic container rather than thick glass. Oxygen can diffuse through the thin plastic and oxidize your wine (same idea as using a flex-tank instead of a barrel for aging). I'd suggest you get some additional glass containers for the next batch. A couple different sizes is good to allow you to eliminate head-space.

 

[Terry_b]

Thank you all for your knowledge and help.
Oxidisation it is.
They were originally in two other demijohns, before siphoning to leave behind some sediment, but only a little fuller than shown.

So I'm lucky to have only one bad one!

Having just read up a bit more, I think next year I need to to up with grape juice. Unless there is a better way?

Out of interest would you advise adding a little juice to all of the containers, or keeping some "pure" with just home grown fruit, and adding more juice into the last one(s).
Or is that just personal taste?

Thanks again.

 

[winemaker81]

@Terry_b, it's all personal taste.

For this year's topup? I recommend topping up with a compatible wine -- it may change the overall flavor, but if you're satisfied with the result, it does not matter. What kind of grapes do you have? Either pick a wine that tastes similar or one that is relatively neutral in flavor.

For next year -- plan to make more wine than your container(s) will hold, so you have topup. You are limited by the grapes you grow, so things may not work out neatly regarding fitting the containers. Another option is to add fresh fruit juice, say apple juice, to the grapes when fermenting to extend the amount. This will change the flavor, but if you are happy with it? Cool!

Start collecting smaller bottles to hold the extra that doesn't fit in your main container(s).

While I don't normally recommend screwcap bottles, IF fermentation is 100% completed, they are fine to use for short term storage of topup wine. Screw the cap down tight and flip upside down. If it doesn't leak, it's fine. Start collecting smaller bottles (375 ml, 750 ml, etc) now so you're set for next year.

Food grade plastic is fine for primary fermentation -- it's what most of us use. For bulk aging, I recommend glass. Plastic products designed specifically for wine making are fine, but if you're not 100% sure, go with glass.

How did you press your grapes?